Residual gum



Patented Nov. 1, 1938 UNITED STATES PATENT OFFIE ncsmuar. GUM

Frank W. Oorkery, Grafton, Pa.

No Drawing. Applicationnecember 6, 1935, Serlal No. 53,213. Renewed June 9, 1938 8Glaims.

such being benzene, toluene, xylene, trimethyl benzene, ethyl benzene, coumarone, indene, cu-

mene, cymene, hemmilithene, hydrindene, and

in general methyl, ethyl, propyl and amyl ad:

1 dition or substitution products of the benzene ring group of aromatic chemicals. In subjecting the light oil to a purifying acid wash, and in distilling the light oil, liquid residue comprising lower polymers, reaction products, and materials of relatively heavy molecular structure remains.

' This residual material is known as still residue.

Similar products are obtained from benzol stills,

and from the acid purification oi the light oil out known as crude solventnaphtha. The residue obtained from flnal stills is known as pure still" residue, and the residue obtained from initial stills is known as crude still residue.

My invention relates to a treatment of still residue as obtained from any of these processes,

or to the treatment 01' a mixed still residue comprising the liquid residuum obtained in any two or more of the described purification processes.

Still residue, as it occurs residually'from the treatment of coalderived liquids, is a substantially useless material, its use under certain conditions and variations as a dispersing agent and softener in the compounding of rubber being the only use of any importance heretofore found for it. I have discovered that the still residue, taken as a whole, comprising various components occurring either as monomers or as lower polymers, possesses to a substantial extentthe quality of unsaturation, and that, by taking advantage of this unsaturated condition of the material, it-may be as a whole oxidized to produce an elastic and pliable material, which is us- I able for various purposes. I may give a typical example of the procedure by means of which the liquid and relatively useless still residue is converted into a useful gum.

Taking astill residue from mixed sources, I have introduced this liquid material into a vessel provided with coils for circulating steam, or other heating medium, and provided with perforated coils connected with a blower, for introducing air under pressure. Initially. I heated the still residue to a temperature approximating F., in order to increase the fluidity oi the material and facilitate the dispersion of air through it, and then introduced, adjacent the bottom oi the vessel, air in .iinely divided streams, which passed upwardly through the body of the still residue. In so doing, the air. was introduced under such pressure that it was capable, in a dispersed condition, of penetrating 10 the body of the liquid.

The introduction 01. air was continued for a period of two days, while maintaining the still residue at the .approximate temperature of 175 F. At the expiration of that period, a notice- 1 able thickening of the still residue had occurred, indicating the progress of oxidation, and rendering it necessary to increase the temperature of the treatment, in order to maintain the material in condition permitting the passage of air 20 .still residue in order adequately to maintain the still residue in a condition suitable for the dispersion of air therein.

I have found it desirable that the tempera,- 35 ture conditions throughout the continuance of the oxidizing process bemoderate, and to minimize the temperature during the initial stages of the process, in order to minimize vaporization of the lower polymers comprised in the still resi- 40 due and of unpolymerized materials comprised in it. By so doing, the resultant product contains in oxidized form substantially the entire content of the still residue iorming the starting material. It is possible to increase the temper- 45 ature of the treatment from time to time throughout the process, as oxidation proceeds, without loss of the lighter content of still resi due, sincethe progress of oxidation tends to render the components of the still residue less vola- 50 tile, and since, in the initial stages of the process, oxidation is effected preponderantly upon the lighter and more volatile components of the material. The lighter components of the still residue on becoming oxidised are thereby ran- 56 pliable gummy mass which has a melting-range as high as 175 F. to 185 F. In its physical qualities the product is a gummy mass, rather than a resin, since it is not brittle, and since it does not possess the tackiness' of the soft resins containing, as they do, a large proportion of unsaturated lower polymers. It should further be noted in connection with the plastic gum that it may be bent in layers without breaking, and that a thin deposited film of the gum is elastic, rather than brittle.

The product does, howeverydifier substantially from an asphalt, inv that it is transparent in solution, and in the form of a film. While the oxidized gum appears black in mass, it is definitely reddish in solution, and upon drying as a film is relatively colorless. The gum has good solubility in the aromatic hydrocarbon solvents and in the mixed aromatic and paraflin solvents. If also the process be discontinued at a point to provide aresultant gum having a melting-point of F. or lower, such gum has good solubility in the paraffin hydrocarbon solvents.

As included in coating compositions, it presents advantage over blown asphalts, in that its transparency permits it to serve as a vehicle for pigments, and that as unpigmented it is of attrac tive appearance.- It also presents advantage over asphalt in the fact that it is not readily'dissolved by oils, as is blown asphalt, and therefore forms a more resistant and permanent film. It may advantageously be used as a substitute for asphalt in roofing compositions.

As a substitute for resin oil mixtures, the plastic gum may be used with advantage in the manufacture of mastic floor tile, linoleum, oil cloth, and similar products, since its properties render it generally suitable as a substitute for resin oil mixtures, cotton seed pitch, stearine pitch, and other vegetable pitches. Because of its substantially decreased iodine value, the plastic gum is superior to otherwise treated still residue used with or without oil admixture in compounding rubber, since its low iodine value makes for stability in the rubber, Being transparent, it is particularly suitable for use in the waterproofing of paper and other absorbent materials.

' To describe the property of still residue which led to my invention, and to indicate the technology involved in producing astill residue of changed quality, it should be noted that I have found the untreated still residue, of mixed origin,

to have an iodine value of from 130 to 150. After the complete blowing treatment, set forth above as exemplary, the still residue, with a meltingrange of F. to F., had an iodine value of between 65 and 70. 7

It should be explained that the increase in viscosity and melting-point of the still resin is due primarily to oxidation of the still residue, without any substantial polymerizing efl'ect during the blowing treatment. It is for this reason that the gum, formed as a product of oxidation, has a relatively high melting-point with respect to its consistency, and does not possess the tackiness of synthetic resins of comparable melting-point including a large proportion of heavy oils.

It should be emphasized that substantially the entire content of the initial still residue may be retained in producing the oxidized gum, no substantial portion of it being distilled oil either before or after the oxidizing treatment. This sounds in economy, since it is unnecessary to waste either the heavier end of the still residue, or the lighter unpolymerized, or but slightly polymerized, components of the still residue.

More important, it results in producing a gum having the qualities which I desire. That is, by retaining and treating the major content of the still residue, I am able to obtain a gum which exhibits neither the brittleness of a hard resin, nor the fluidity of a heavy oil.

Assuming that the more highly polymerized initial components of the still residue are those of lowest iodine value. and that the lowest polymers and unpolymerized components of the still residue are those having the highest iodine value, the average of the oxdizing saturation in the still residue as a whole results in the production of a pliable, elastic solid which has apparently throughout its components a molecular weight varying throughout a relatively narrow range. This is indicated by the relatively good solubility of the gum.

While utilizing the entire initial'content of the still residue, it is possible widely to vary the qualities of the material produced. Thus by discontinuing the blowing treatment at an intermediate point, there isobtained a gum of lower meltingpoint, which gum is, as noted above, soluble in thecommon paraflln hydrocarbon solvents. In such intermediate product it is in chiefly the lighter components that oxidation has been effected, since, as noted, it is these components which possess the higher initial unsaturation, and are, therefore, the more readily oxidized. An apparent uniformity in molecular weight throughout the treated material is thus present even though the process be not carried forward to the point of producing a resin having a melting-range approximating 175 F. to 185 F. If th oxidizing treatment be discontinued at a relatively early stage, such, for example, as to give a product melting at 120 F., the product is suitable for use as an adhesive or as a plasticizer.

Initial still residue, possessing substantial un- Observing the factors of time, temperature, and distribution and volume of air, my process may thus be modified by reduction in the time-temperature factor, or in the'oxidizing factor. Also assuming that a uniform and sufllcient supply of air is employed, the melting point and cohesion of the resultant gum may, within relatively narrow limits, be increased by continuing the process beyond the point illustrated in the above specific example, under conditions of increased temperature.

The example given approximates the maximum treatment which the still residue may be gluon,

since substantial continuance of the treatment results in such increased density of the material solvents.

In speaking of the entire content of the still residue, I do not specifically have, reference to the use of a still residue of mixed origin. Coalderived still residue, as obtained residually in any one of the various treating operations by which it is produced, may be treated by itself, without variation from the procedure employed in oxidizing a still residue of mixed origin. It is, of course, wasteful to distill off any perceptible proportion of the entire still residue content during the progress of oxidation. Loss of a relatively small proportion of the still residue content does not seriously detract from the value of the resultant gum. Loss of still residue amounting to 15% or more of the initialvolume does, however, seriously impair the elasticity of the gum, tending to give it the brittleness commonly associated with the hard resins.

I claim as my invention:

1. The herein described method of treating liquid still residue from the treatment of cokeoven light oils to increase its saturation and decrease its fluidity without substantial polymerization therein which consists in oxidizing the still residue by distributing gaseous oxygen w through a liquid body containing in approximate entirety the initial components of the still residue from the treatment of coke-oven light oils under temperature conditions sufliciently elevated to maintain the still residue in a condi- 5 tion of liquidity suitable for the dispersion of gaseous oxygen therethrough and below a point at which substantial vaporization of the still residue is caused.

2. The herein described method of producing a residual elastic gum from liquid still residue from the treatment of coke-oven light oils without substantial polymerization therein which comprises oxidizing the still residue by distributing gaseous oxygen through a liquid body of the still residue from the treatment of coke-oven light oils at an initial temperature sufliciently elevated to render the still residue adequately liquid for the dispersion of gaseous oxygen therethrough, and continuing distribution of gaseous oxygen through the still residue throughout a period of time sufllciently extended to change the still residue by oxidation from an oily liquid to a pliable gum under temperature conditions progressively more elevated in approximate pro- 5 portion to the decrease in liquidity of the still residue due to progressive oxidation thereof, and under conditions of treatment suillciently moderate to avoid removal of as much as 15% the volume of the still residue treated.

3. The herein described method of producing a.

residual gum from liquid still residue from the treatment of coke-oven'light oils without substantial polymerization therein which comprises oxidizing the still residue by distributing gaseous oxygen through a liquid body of the still residue from the treatment of coke-oven light oils at an initial temperature sufllciently elevated to render the still residue adequately liquid for the dispersion of gaseous oxygen therethrough, andcontinuing the .progress of oxidation by continued distribution of gaseous. oxygen through the still residue to a point of oxidation at which the melting-range oi the still residue approximates *F. to F. under temperature conditions progressively more elevated in approximate proportion to the decrease in liquidity of the still residue due to progressive oxidation thereof, and under conditions of treatment sufliciently moderate to avoid removal of as much as 15% the volume of the still residue treated.

4.-The herein described method of treating liquid still residue from the treatment of cokeoven light oils to increase its saturation and decrease its fluidity without substantial polymerization in the still residue which comprises oxidizing the still residue by distributing gaseous oxygen through a liquid body of the still residue from the treatment of coke-oven light oils under temperature conditions not substantially lower than 175 F. which are sufliciently elevated to render the still residue adequately liquid for the dispersion of gaseousoxygen therein, and under conditions of treatment sufliciently moderate to avoid removal of as much as 15% the volume of the still residue treated.

5. The herein described method of treating liquid still residue from the treatment of cokeoven light oils to increase its saturation anddecrease its fluidity without substantial polymerization in the-still residue which comprises oxidizing the still residue by distributing gaseous oxygen through a liquid body of the still residue from the treatment of coke-oven light oil under temperature conditions not substantially lower than 175 F. sufficiently elevated to render the still residue adequately liquid for the dispersion or gaseous oxygen therein, and as oxidation of the still residue proceeds progressively elevating the temperature conditions of the process in substantial accordance with the progressive decrease in the fluidity of the still residue attendant upon oxidation therein, and under conditionspi treatment sufliciently moderate to avoid removal of as much as 15% the volume of the still residue treated.

6. The herein described method of producing a residual elastic gum from liquid still residue from the treatment of coke-oven light oils without substantial polymerization therein which comprises oxidizing the still residue by distributing gaseous oxygen through a liquid body of the still residue from the treatment of coke-oven light oils under temperature conditions not substantially lower than 175 F. suiiiciently elevated to render the still residue'adequately liquid for the dispersion of gaseous oxygen therein, and continuing the progress of oxidation by continued distribution of gaseous oxygen through the still residue to a point, of oxidation at which the melt-' ing-range of the still residue approximates 175 F. to 185 F. under temperature conditions pro- 'essively more elevated up to a maximum temperature approximating 245 F. in approximate proportion to progressive decrease in the liquidity of the still residue. t

7. The herein described residual gum produced by oxidation and without substantial polymerization from liquid still residue from the treatment of coke-oven light oils having an initial iodine value not substantially. lower than 130,

which gum is a pliable solid transparent in solution and in a film which melts not substantially lower than 175 E, which has a greatly reduced iodine value, and which comprises not less than 85% the initial volume of the still residue treated.

8. The herein described residual gum produced by oxidation and without substantial polymerization from liquid stlll residue from the treatment of coke-oven light oils comprising approximately the entire still content of said still residue and having an initial iodine value not substantially lower than 130, which gum is a pliable solid transparent in solution and in a film which melts not substantially lower than 175 F. and which has an iodine value not substantially higher than FRANK W. CORKERY. 

